The present invention relates to the art of cutting and trimming devices and more particularly to paper trimming machines employing sawing-type cutting actions.
Conventional paper trimming machines generally use guillotine-type blades driven at substantially perpendicular angles to the material being cut so as to shear the material along the desired line. Because of the extreme angle at which the cutting edge is driven with respect to the work material, substantial force must be imparted to the blade to complete the cutting action. These devices provide clean and even cuts, but are usually quite large and bulky. Also, these machines are inappropriate for many uses because of the limited amount of material which can be cut with a single stroke of the cutting blade.
Sawing-type cutting actions are preferable in these applications because the cutting action is continuous and may proceed substantially without interruption. An additional advantage of such machines lies in the size and weight reductions which may be realized over the previously described, guillotine-type machines. These devices, typically band saw machines, have met with difficulties, however, due to the tendency of the cutting edge to tear and crush the material being severed. An example of this type of trimming device is described in U.S. Pat. No. 1,635,165.
It is, of course, economically desirable to have a band saw blade which may be resharpened. This is commonly difficult because of the complex shape of the cutting edges used. Also, resharpening of the blades characteristically causes changes in the shape of the cutting edge and a resultant diminution in quality of the cut provided thereby.